Engine driven power supplies with output reduction

ABSTRACT

Engine driven power supplies with output reduction are disclosed. An example engine-driven welding power supply for providing a welding-type output includes an engine, a generator mechanically linked to the engine, power conditioning circuitry, and a controller. The generator generates output power based on mechanical input from the engine. The power conditioning circuitry converts the output power from the generator to welding-type power based on a commanded welding-type output. The controller reduces a welding-type output of the power conditioning circuitry from the commanded welding-type output by an amount proportional to a difference between a speed of the engine and a commanded engine speed while monitoring the difference between the speed of the engine and the commanded engine speed, decreases the welding-type output until the difference between the speed of the engine and the commanded engine speed decreases, and increases the welding-type output as the difference between the speed of the engine and the commanded engine speed decreases until the welding-type output equals the commanded welding-type output.

BACKGROUND

This disclosure relates generally to welding systems and, moreparticularly, to engine driven power supplies with output reduction.

An electronically controlled welding power source will attempt todeliver whatever output power the power source is commanded to deliver.If the engine does not have enough power to supply the commanded load, afold back circuit reduces the load in an attempt to match the availableengine power.

SUMMARY

Engine driven power supplies with output reduction are disclosed,substantially as illustrated by and described in connection with atleast one of the figures, as set forth more completely in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an example engine driven power supplyimplementing output reduction in accordance with aspects of thisdisclosure.

FIG. 2 shows corresponding graphs of a welding-type output, an enginespeed, and a reduction in the commanded welding-type output for anexample in which an operator attempts to perform a welding-typeoperation when the engine of FIG. 1 is at an idle speed.

FIG. 3 shows corresponding graphs of a welding-type output, an enginespeed, and a reduction in the commanded welding-type output for anexample in which an operator attempts to perform a welding-typeoperation requiring more power than can be provided by the engine.

FIG. 4 is a flowchart representative of example machine readableinstructions which may be executed to implement the controller of FIG. 1to control a welding-type output.

DETAILED DESCRIPTION

To avoid stalling, conventional engine-driven welders reduce an outputcommand by an amount that is proportional to the amount that the enginespeed (e.g., revolutions per minute, or RPM, of the engine) is below thenormal operating speed. However, conventional engine-driven weldersreduce the output by more than is actually necessary to allow the engineto accelerate up to rated speed. High reductions in output can causewelding issues for an operator, and particularly when the operator isattempting to start and establish a welding arc from an idle enginespeed. In addition, different engines have different speed and/or torquecharacteristics, and one engine may be able to accelerate more or lessunder load than a different engine. Furthermore, engines withturbochargers have a different load pick-up characteristic thannon-turbo engines. Operating conditions such as altitude, the conditionof the fuel, and/or the conditions of air filters can also influence anengine response. Due to the variety of potential conditions, one set ofvalues in an RPM fold back control scheme may not be appropriate for aagiven combination of an engine and operating conditions, and someconditions are beyond an engine manufacturer's control.

Disclosed examples improve the adaptability of an engine to a load andoperating conditions by only reducing an output command (relative to anoutput requested or programmed by an operator) by an amount that permitsthe engine to accelerate to the rated speed to support the load. Someexamples start at a lower reduction in the output command and furtherreduce the output command until the engine reaches begins accelerating.By reducing the change in the output command, undesired effects on thework being performed by the operator is also reduced.

Disclosed examples are implemented in software executed by a controller,which that monitors engine speed (e.g., RPM) and generates a differencevalue or error value when an RPM is below the commanded operating enginespeed. The different value is calculated as the RPM setpoint-measuredengine RPM. Disclosed examples reduce the output command by an amountthat is proportional to the difference value, but is also limited to asmall reduction. The change in the difference value is monitored. If thedifference value is reducing (e.g., the engine is accelerating) thecommand is not reduced any further. In some examples, when the enginereaches the commanded speed and is no longer accelerating, the systemstops monitoring the change in the difference and only reduces thecommand by the amount proportional to the error. In some examples,monitoring the change in the difference and increasing the reduction incommand is only used during engine acceleration. In some instances, thesystem may become unstable when continuing to adjust for a change in thedifference when the engine reached the commanded speed.

If the difference value is not reducing (e.g., the engine does not haveenough power to supply the commanded output), the command is furtherreduced, and the difference value is further monitored to determine ifthe error is decreasing. As a result, in some examples the outputcommand is only reduced the minimum amount required to allow the engineto accelerate to rated speed.

Disclosed examples improve the stability of the welding arc whenstarting a weld from an idle engine condition. In contrast, conventionalRPM foldback techniques are subject to reducing the output more than isrequired to permit the engine to accelerate and also causing the weldingarc to snuff out, which is objectionable to the operator. In such acase, the engine RPM will then surge up as the load is removed, cause areduction in the output command and, when the operator attempts tore-strike and establish a welding arc, cause the engine RPM to fallagain and potentially cause the arc will snuff out again.

In some examples, when the engine driven welding power source isattempting to supply a high power load, such as during an arc gougingprocess, the power requirements may exceed the available engine power.As a result of exceeding the available engine power, example enginedriven welding power sources continuously operate in the output foldbackmode, where the welding-type output is reduced only so as to match theavailable engine power. In contrast, conventional engine driven weldersmay reduce the output beyond what is required to match the engine power,which can cause the output power and engine RPM to oscillate anddestabilize the welding-type process, which is undesirable to theoperator. Disclosed examples create more stable operating conditionsthan conventional techniques.

Conventional engine RPM foldback techniques may permit an engine tobecome effectively stuck at an RPM lower than the normal operating speedwhen coming up from idle. Disclosed examples prevent such sticking ofthe engine RPMs by monitoring the change in error. If the error is notchanging, disclosed examples further reduce the welding-type output topermit the engine to accelerate.

Disclosed examples enable a dynamic RPM foldback technique that permitsimprovement over conventional techniques for different engines and/ordifferent engine operating conditions. Thus, disclosed examples reduceor avoid the need to tune the foldback technique to a particular engine,which may not account for different sets of operating conditions.

The term “welding-type output,” as used herein, refers to an outputsuitable for welding, plasma cutting, induction heating, CAC-A and/orhot wire welding/preheating (including laser welding and lasercladding).

FIG. 1 is a schematic diagram of an example engine driven power supply100 implementing output reduction. The example engine driven powersupply 100 includes an engine 102, a generator 104, power conditioningcircuitry 106, and a controller (e.g., a control circuit) 108.

The engine 102 is mechanically coupled or linked to a rotor of thegenerator 104. The engine 102 is controllable to operate at multiplespeeds, such as an idle (e.g., no or minimal load speed) and a maximumspeed (e.g., the maximum rated power of the engine 102). The enginespeed may be increased and/or decreased based on the load. The generator104 generates output power based on the mechanical input from the engine102.

The power conditioning circuitry 106 converts output power from thegenerator 104 to welding-type power based on a commanded welding-typeoutput. The power conditioning circuitry 106 provides current at adesired voltage to an electrode 110 and a workpiece 112 to perform awelding-type operation. The power conditioning circuitry 106 mayinclude, for example, a switched mode power supply or an inverter. Powerconditioning circuitry may include a direct connection from a powercircuit to the output (such as to the weld studs), and/or an indirectconnection through power processing circuitry such as filters,converters, transformers, rectifiers, etc.

A user interface 114 enables selection of a commanded power level orwelding-type output, such as a current or voltage level to be used forwelding-type operations. The user interface 114 additionally oralternatively enables selection of one or more speeds for the engine 102(e.g., in RPM), such as an idle engine speed and/or engine speed underload.

The controller 108 receives an engine speed input from the engine 102 ora sensor, and obtains the commanded engine speed and/or the commandedwelding-type output from the user interface 114. When the controller 108determines that a load on the welding-type output is causing the enginespeed to drop or to fail to accelerate to match the load, the controller108 reduces the welding-type output from the commanded welding-typeoutput to enable the engine speed to increase.

In response to detecting a load or an increase in the load beyond thecapacity of the engine 102, the controller 108 reduces the welding-typeoutput of the power conditioning circuitry 106 from the commandedwelding-type output by an amount proportional to a difference betweenthe speed of the engine 102 and the commanded engine speed whilemonitoring the difference between the speed of the engine and thecommanded engine speed. For example, if the engine 102 is at an idlespeed when a load is added, the controller 108 decreases thewelding-type output by a larger amount than if the engine decreases fromthe commanded speed due to an increased load on the engine. Thecontroller 108 may monitor the difference between the speed of theengine and the commanded engine speed by comparing successive samples ofthe difference between the speed of the engine 102 (e.g., from RPMfeedback 116) and the commanded engine speed to determine whether thedifference is increasing, decreasing, or remaining the same.

When the controller 108 detects a condition to cause a decrease in thewelding-type output, the controller 108 continues to decrease thewelding-type output until the difference between the speed of the engine102 and the commanded engine speed begins to decrease (e.g., when theengine 102 begins accelerating). As the different between the speed ofthe engine 102 and the commanded engine speed, the controller 108increases the welding-type output as the until the welding-type outputequals the commanded welding-type output.

The controller 108 controls the welding-type output by controlling thepower conditioning circuitry 106 or by controlling a field current ofthe generator 104. For example, the controller 108 may decrease thewelding-type output by decreasing at least one of a current output ofthe power conditioning circuitry 106 or a voltage output of the powerconditioning circuitry 106. The controller 108 may control a switchedmode power supply of the power conditioning circuitry 106 to reduce anoutput power and/or limit power consumed by the load connected to thepower conditioning circuitry. Additionally or alternatively, thecontroller 108 may reduce the welding-type output by decreasing amagnitude of the field current in the generator 104 and/or increase thewelding-type output by increasing the magnitude of the field current inthe generator 104.

In some examples, the controller 108 decreases the welding-type outputin response to determining that the initial reduction in thewelding-type output (e.g., by the amount proportional to the differencebetween the speed of the engine and the commanded engine speed) does notresult in an acceleration in the speed of the engine 102. The controller108 may decrease the welding-type output by a first amount, determinewhether the speed of the engine 102 has increased and, in response todetermining that the speed of the engine 102 has not increased, decreasethe welding-type output by a second amount. The controller 108 maycontinue to decrease the welding-type output and monitor to determinewhether the decrease results in acceleration of the engine 102. In thismanner, the controller 108 may be able to minimize a reduction in thewelding-type output to a reduction necessary to enable the engine 102 toaccelerate, which reduces the effect of the welding-type outputreduction on the welding-type operation being performed.

In some examples, the controller holds the welding-type output whilemonitoring the difference between the speed of the engine 102 and thecommanded engine speed for a threshold time duration prior to decreasingthe welding-type output. The hold time may avoid affecting thewelding-type operation in situations in which the engine 102 is capableof accelerating to the rated speed without assistance from the outputcontrol. Additionally or alternatively, the controller 108 may attemptto reduce the load or the welding-type output without direct controlover the weld arc. As an example, the controller 108 may reduce a wirefeed speed of a wire feeder that is part of a welding-type operation.The reduction in wire feed speed may be accomplished by communicationbetween the controller 108 and the wire feeder, and can influence a weldoperator to slow the welding travel speed and reduce the resultingwelding load.

The controller 108 may include digital and/or analog circuitry, discreteor integrated circuitry, microprocessors, digital signal processors(DSPs), field programmable gate arrays (FPGAs), and/or any other type oflogic circuits. The example controller 108 may be implemented using anycombination of software, hardware, and/or firmware. The controller 108executes machine readable instructions 118 which may be stored on one ormore machine readable storage device(s) 120 such as volatile and/ornon-volatile memory, hard drives, solid state storage, and the like.

FIG. 2 shows corresponding graphs 200, 202, 204 of a welding-type output206, an engine speed 208, and a reduction in the commanded welding-typeoutput 210 for an example in which an operator attempts to perform awelding-type operation when the engine 102 of FIG. 1 is at an idlespeed. The graphs 202, 204 also illustrate a commanded engine speed 212and a commanded welding-type output 214.

Prior to a first time 216 illustrated in the graphs 200, 202, 204, nowelding-type output is being attempted by an operator (e.g., nowelding-type operation is being performed). The engine 102 is operatingan idle speed 218.

At the first time 216, the operator initiates a welding-type output by,for example, striking a welding arc. In response, the welding-typeoutput from the power conditioning circuitry 106 of FIG. 1 increases asthe load on the welding-type output increases. However, because the loadis too high, the engine 102 is prevented from accelerating and, in somecases, may further decelerate. The controller 108 monitors a difference220 between the engine speed 208 and the commanded engine speed 212.

Because the difference 220 between the engine speed 208 and thecommanded engine speed 212 does not decrease after the first time 216,at a second time 222 the controller 108 reduces the welding-type output206 by a first amount. As shown in the graphs 200, 204, the reduction210 in the welding-type output corresponds to the decrease in thewelding-type output 206. The controller 108 continues monitoring adifference 220 between the engine speed 208 and the commanded enginespeed 212 by comparing successive samples of the engine speed 208 to thecommanded engine speed 212.

Because the difference 220 between the engine speed 208 and thecommanded engine speed 212 does not decrease after the second time 222,at a third time 224 the controller 108 further reduces the welding-typeoutput 206 while monitoring the difference 220. In the example of FIG.2, the controller 108 decreases the welding-type output 206 (e.g.,increases the reduction 210) until a fourth time 226, at which theengine speed 208 begins to increase and the difference 220 between theengine speed 208 and the commanded engine speed 212 begins to decrease.

After the fourth time 226, the controller 108 increases the welding-typeoutput 206 (e.g., decreases the reduction 210) as the difference 220between the engine speed 208 and the commanded engine speed 212decreases (e.g., as the engine speed 208 increases) until thewelding-type output 206 equals the commanded welding-type output 214.

FIG. 3 shows corresponding graphs 300, 302, 304 of a welding-type output306, an engine speed 308, and a reduction 310 in the commandedwelding-type output for an example in which an operator attempts toperform a welding-type operation requiring more power than can beprovided by the engine 102. The graphs 300, 302, 304 also illustrate acommanded engine speed 312 and a commanded welding-type output 314.

Prior to a first time 316, an operator is performing a welding-typeoperation that creates a load on the engine 102, and the engine 102 isoperating at the commanded engine speed 312. At the first time 316, theload on the welding-type output 306 increases above a maximum load thatcan be sustained by the engine 102. As a result, the engine speed 308begins to drop and a difference 318 between the engine speed 308 and thecommanded engine speed 312 increases. The controller 108 monitors thedifference 318 while waiting a time duration after the first time 316until a second time 320.

Because the difference 318 between the engine speed 308 and thecommanded engine speed 312 does not decrease after the first time 316,at a second time 320 the controller 108 reduces the welding-type output306 by a first amount. As shown in the graphs 300, 304, the reduction310 in the welding-type output corresponds to the decrease in thewelding-type output 306. The controller 108 continues monitoring adifference 318 between the engine speed 308 and the commanded enginespeed 312 by comparing successive samples of the engine speed 308 to thecommanded engine speed 312.

Because the difference 318 between the engine speed 308 and thecommanded engine speed 312 does not decrease after the second time 320,at a third time 322 the controller 108 further reduces the welding-typeoutput 306 while monitoring the difference 220. In the example of FIG.3, the controller 108 decreases the welding-type output 306 (e.g.,increases the reduction 310) until a fourth time 324, at which theengine speed 308 begins to increase and the difference 318 between theengine speed 308 and the commanded engine speed 312 begins to decrease.

After the fourth time 324, the controller 108 increases the welding-typeoutput 306 (e.g., decreases the reduction 310) as the difference 318between the engine speed 308 and the commanded engine speed 312decreases (e.g., as the engine speed 308 increases) until thewelding-type output 306 equals the commanded welding-type output 314.

FIG. 4 is a flowchart representative of example machine readableinstructions 400 which may be executed to implement the controller 108of FIG. 1 to control a welding-type output. The example instructions 400of FIG. 4 may be executed to reduce the welding-type output of the powerconditioning circuitry of FIG. 1 to permit the engine speed to increaseto a commanded engine speed.

At block 402, the controller 108 determine a commanded welding-typeoutput. For example, the controller 108 may receive a current or voltageselection via the user interface 114 of FIG. 1.

At block 404, the controller 108 determines whether a welding-typeoutput load is present on an output of the power conditioning circuitry106. For example, the controller 108 may receive measurement(s) ofoutput current, output voltage, and/or output power from the powerconditioning circuitry 106 or from one or more sensor(s). If no load ispresent (block 404), control returns to block 402.

When a welding-type output load is present on an output of the powerconditioning circuitry 106 (block 404), at block 406 the controller 108determines a commanded engine speed to provide the power for the load.For example, the commanded engine speed may be set by the user interface114 and/or calculated based on the requirements of the load.

At block 408, the controller 108 monitors a difference between a speedof the engine 102 (e.g., in RPM) and the commanded engine speed (inRPM). For example, the controller 108 may monitor the differences 220 or318 in the examples of FIGS. 2 and 3.

At block 410, the controller 108 determines whether the differencebetween the speed of the engine 102 and the commanded engine speed isless than a threshold. The threshold may represent an engine speed thatis not likely to result in stalling of the engine 102. If the differencebetween the speed of the engine 102 and the commanded engine speed isless than the threshold (block 410), control returns to block 402).

If the difference between the speed of the engine 102 and the commandedengine speed is at least the threshold different (block 410), at block412 the controller 108 determines whether the difference between thespeed of the engine 102 and the commanded engine speed decreased.

If the difference between the speed of the engine 102 and the commandedengine speed has not decreased (block 412), at block 414 the controller108 controls the power conditioning circuitry 106 and/or the generator104 to decrease the welding-type output. On the other hand, if thedifference between the speed of the engine 102 and the commanded enginespeed has decreased (block 412), at block 416 the controller 108controls the power conditioning circuitry 106 and/or the generator 104to increase the welding-type output. After increasing the welding-typeoutput (block 416) or decreasing the welding-type output (block 414),control returns to block 408. When the engine speed increases to reachthe commanded speed and is no longer accelerating after increasing atblock 416 (e.g., the difference is less than the threshold at block410), the controller 108 stops monitoring the change in the differenceto avoid instability in the system. When the controller 108 againidentifies that the difference is at least the threshold difference atblock 410, the controller 108 may then monitor the change in thedifference at block 412.

The present devices and/or methods may be realized in hardware,software, or a combination of hardware and software. The present methodsand/or systems may be realized in a centralized fashion in at least onecomputing system, processors, and/or other logic circuits, or in adistributed fashion where different elements are spread across severalinterconnected computing systems, processors, and/or other logiccircuits. Any kind of computing system or other apparatus adapted forcarrying out the methods described herein is suited. A typicalcombination of hardware and software may be an processing systemintegrated into a welding power supply with a program or other codethat, when being loaded and executed, controls the welding power supplysuch that it carries out the methods described herein. Another typicalimplementation may comprise an application specific integrated circuitor chip such as field programmable gate arrays (FPGAs), a programmablelogic device (PLD) or complex programmable logic device (CPLD), and/or asystem-on-a-chip (SoC). Some implementations may comprise anon-transitory machine-readable (e.g., computer readable) medium (e.g.,FLASH memory, optical disk, magnetic storage disk, or the like) havingstored thereon one or more lines of code executable by a machine,thereby causing the machine to perform processes as described herein. Asused herein, the term “non-transitory machine readable medium” isdefined to include all types of machine readable storage media and toexclude propagating signals.

While the present method and/or system has been described with referenceto certain implementations, it will be understood by those skilled inthe art that various changes may be made and equivalents may besubstituted without departing from the scope of the present methodand/or system. In addition, many modifications may be made to adapt aparticular situation or material to the teachings of the presentdisclosure without departing from its scope. For example, block and/orcomponents of disclosed examples may be combined, divided, re-arranged,and/or otherwise modified. Therefore, the present method and/or systemare not limited to the particular implementations disclosed. Instead,the present method and/or system will include all implementationsfalling within the scope of the appended claims, both literally andunder the doctrine of equivalents.

What is claimed is:
 1. An engine-driven welding power supply forproviding a welding-type output comprising: an engine; a generator,mechanically linked to the engine, and configured to generate outputpower based on mechanical input from the engine; power conditioningcircuitry to convert the output power from the generator to welding-typepower based on a commanded welding-type output; and a controllercomprising circuitry configured to, in response to determining that adifference between a speed of the engine and a commanded engine speedsatisfies a threshold difference: reduce a welding-type output of thepower conditioning circuitry from the commanded welding-type output byan amount proportional to a difference between a speed of the engine anda commanded engine speed while monitoring the difference between thespeed of the engine and the commanded engine speed; decrease thewelding-type output until the difference between the speed of the engineand the commanded engine speed decreases; and increase the welding-typeoutput as the difference between the speed of the engine and thecommanded engine speed decreases until the welding-type output equalsthe commanded welding-type output.
 2. The engine-driven welding powersupply as defined in claim 1, wherein the controller is configured toreduce the welding-type output by the amount proportional to thedifference between the speed of the engine and the commanded enginespeed in response to detecting that a load is present on thewelding-type output or in response to detecting an increase in the loadpresent on the welding-type output.
 3. An engine-driven welding powersupply for providing a welding-type output comprising: an engine; agenerator, mechanically linked to the engine, and configured to generateoutput power based on mechanical input from the engine; powerconditioning circuitry to convert the output power from the generator towelding-type power based on a commanded welding-type output; and acontroller comprising circuitry configured to: reduce a welding-typeoutput of the power conditioning circuitry from the commandedwelding-type output by an amount proportional to a difference between aspeed of the engine and a commanded engine speed while monitoring thedifference between the speed of the engine and the commanded enginespeed; decrease the welding-type output until the difference between thespeed of the engine and the commanded engine speed decreases; andincrease the welding-type output as the difference between the speed ofthe engine and the commanded engine speed decreases until thewelding-type output equals the commanded welding-type output, whereinthe controller is configured to hold the welding-type output whilemonitoring the difference between the speed of the engine and thecommanded engine speed for a threshold time duration prior to decreasingthe welding-type output.
 4. The engine-driven welding power supply asdefined in claim 1, wherein the generator comprises a field windinghaving a field current, the welding-type output is responsive to thefield current, and the controller is configured to control the fieldcurrent.
 5. The engine-driven welding power supply as defined in claim4, wherein the controller is configured to reduce the welding-typeoutput by decreasing a magnitude of the field current and is configuredto increase the welding-type output by increasing the magnitude of thefield current.
 6. The engine-driven welding power supply as defined inclaim 1, wherein the power conditioning circuitry comprises a switchedmode power supply, the controller configured to reduce the welding-typeoutput by controlling the switched mode power supply to reduce theoutput power.
 7. The engine-driven welding power supply as defined inclaim 1, wherein the controller is configured to reduce the welding-typeoutput by limiting power consumed by a load connected to the powerconditioning circuitry.
 8. The engine-driven welding power supply asdefined in claim 1, wherein the controller is configured to monitor thedifference between the speed of the engine and the commanded enginespeed by comparing successive samples of the difference between thespeed of the engine and the commanded engine speed to determine whetherthe difference is increasing, decreasing, or remaining the same.
 9. Theengine-driven welding power supply as defined in claim 1, wherein thecontroller is configured to minimize a reduction in the welding-typeoutput to a reduction necessary to enable the engine to accelerate. 10.The engine-driven welding power supply as defined in claim 1, whereinthe controller is configured to decrease the welding-type output inresponse to determining that the reduction in the welding-type output bythe amount proportional to the difference between the speed of theengine and the commanded engine speed does not result in an accelerationin the engine speed.
 11. The engine-driven welding power supply asdefined in claim 10, wherein the controller is configured to decreasethe welding-type output by a first amount, determine whether the speedof the engine has increased and, in response to determining that thespeed of the engine has not increased, decrease the welding-type outputby a second amount.
 12. The engine-driven welding power supply asdefined in claim 1, wherein the controller is configured to decrease thewelding-type output by decreasing at least one of a current output ofthe power conditioning circuitry or a voltage output of the powerconditioning circuitry.
 13. A non-transitory machine readable storagemedium comprising machine readable instructions which, when executed,cause a control circuit of an engine-driven welding power supply to:monitor a difference between a speed of an engine and a commanded enginespeed; detect a load applied to power conditioning circuitry powered bythe engine and a generator that is mechanically linked to the engine; inresponse to detecting the load, reduce a welding-type output of thepower conditioning circuitry from a commanded welding-type output by anamount proportional to the difference between the speed of the engineand the commanded engine speed; decrease the welding-type output untilthe difference between the speed of the engine and the commanded enginespeed decreases; and increase the welding-type output as the differencebetween the speed of the engine and the commanded engine speed decreasesuntil the welding-type output equals the commanded welding-type output,wherein the instructions cause the control circuit to hold thewelding-type output while monitoring the difference between the speed ofthe engine and the commanded engine speed for a threshold time durationprior to decreasing the welding-type output.
 14. The non-transitorymachine readable storage medium as defined in claim 13, wherein theinstructions cause the control circuit to reduce the welding-type outputby the amount proportional to the difference between the speed of theengine and the commanded engine speed in response to detecting that theload is present on the welding-type output.
 15. The non-transitorymachine readable storage medium as defined in claim 13, wherein theinstructions cause the control circuit to control a field current of afield winding in the generator, the welding-type output being responsiveto the field current.
 16. The non-transitory machine readable storagemedium as defined in claim 15, wherein the instructions cause thecontrol circuit to reduce the welding-type output by controlling thegenerator to decrease a magnitude of the field current.
 17. Thenon-transitory machine readable storage medium as defined in claim 15,wherein the instructions cause the control circuit to increase thewelding-type output by controlling the generator to increase a magnitudeof the field current.
 18. The non-transitory machine readable storagemedium as defined in claim 13, wherein the power conditioning circuitrycomprises a switched mode power supply, and the instructions cause thecontrol circuit to reduce the welding-type output by controlling theswitched mode power supply to reduce an output power.
 19. Thenon-transitory machine readable storage medium as defined in claim 13,wherein the instructions cause the control circuit to reduce thewelding-type output by limiting power consumed by the load connected tothe power conditioning circuitry.